There are numerous techniques, methods and apparatus utilized in the biological field that aid in the collection, storage and transfer of various liquid and solid samples. Generally, in order to perform the analysis, the samples are obtained from a source using a swab or other similar sweeping device. Then, the sample is placed on a slide or other storage mechanism for subsequent analysis.
Medical and other biological samples or specimens are obtained for numerous applications and subsequent analysis of the cellular constituents contained therein. Cellular constituents such as DNA, RNA, proteins, and any other substances are taken for subsequent analysis and tests to determine various diseases and illnesses. Genetic material has been used for the purposes of monitoring and diagnosing genetic diseases and blood-borne parasitic diseases such as malaria. Genetic material can further be used for determining paternity and monitoring other unusual cell populations in blood and other fluids.
Analysis of genetic material can be achieved through numerous techniques and utilize various materials. Generally, these techniques and methods involve the initial collection of the genetic material, storage of the genetic material and then subsequent analysis of the genetic material.
The genetic material can be analyzed through a variety of methods including amplification by the polymerase chain reaction (PCR) (PCR Technology: Principles and Applications for DNA Amplification, H. Erlich (ed), Stockton Press, 1989), genotyping, sequencing (Sanger et al (1977) DNA Sequencing with Chain Terminating Inhibitors Proc.Natl.Acad.Sci. 74: 5463), optical density quantitation, Southern and Northern blotting, fluorescent detection, making molecular probes, and cloning (Molecular Cloning: a Laboratory Manual, Sambrook et al., Cold Spring Harbor Laboratory, 1989).
Medical or other biological samples or specimens are “blotted” or otherwise transferred onto Whatman FTA™ or other similar material for subsequent analysis of cellular constituents such as DNA, RNA or proteins for diagnostic purposes or storage of the sample for archiving and subsequent analysis.
Companies such as Cytyc, Inc. (Boxborough, Mass.) currently market a cervical smear apparatus that takes the medical swab and automatically processes it to produce a monolayer of cells on a slide to facilitate optical examination for cancerous and pre-cancerous cellular states. A part of this process involves the formation of the cell monolayer on a track-etched membrane that is then “blotted” onto a standard glass slide for the optical analysis.
Various materials and solid media have been and continue to be utilized to provide a base for performing any desired analysis of the genetic material. Those materials include, for example, filter paper or FTA™-coated materials developed by Flinders University, Australia. In particular, FTA™-coated materials have been successfully utilized for preparing all types of genetic material for subsequent genetic analysis. Based on U.S. Pat. Nos. 5,496,562, 5,756,126, and 5,807,527, it has been demonstrated that nucleic acids or genetic material can be immobilized to a cellulosic-based dry solid medium, support or filter (such as an FTA™ filter). The solid support described is conditioned with a chemical composition that is capable of carrying out several functions: (i) lyse intact cellular material upon contact, releasing genetic material, (ii) enable and allow for the conditions that facilitate genetic material immobilization to the solid support (probably by a combination of mechanical and chaotrophic), (iii) maintain the immobilized genetic material in a stable state without damage due to degradation, endonuclease activity, UV interference, and microbial attack, and (iv) maintain the genetic material as a support-bound molecule that is not removed from the solid support during any down stream processing (as demonstrated by Del Rio et al (1995) BioTechniques. Vol. 20: 970-974).
The usefulness of the FTA™ cellulosic filter material described in U.S. Pat. Nos. 5,496,562, 5,756,126, and 5,807,527 has been illustrated for several nucleic acid techniques such as bacterial ribotyping (Rogers, C & Burgoyne, L (1997) Anal. Biochem. Vol. 247: 223-227), detection of single base differences in viral and human DNA (Ibrahim et al (1998) Anal. Chem. Vol. 70: 2013-2017), DNA databasing (Ledray et al (1997) J. Emergency Nursing. Vol. 23, No. 2: 156-158), automated processing for STR electrophoresis (Belgrader, P & Marino, M (1996) L.R.A. Vol. 9: 3-7, Belgrader et al (1995) BioTechniques. Vol. 19, No. 3: 427-432), and oligonucleotide ligation assay for diagnostics (Baron et al (1996) Nature Biotech. Vol 14: 1279-1282).
Currently, cellular material is applied to FTA™ filter media, and once the cellular material is applied, it forms a spot on the FTA™ filter. From this spot, small punches can be taken; each small punch will have immobilized to it enough nucleic acid or genetic material to facilitate a single downstream process such as a PCR reaction. As the two primers administered to a PCR reaction are presented in solution, it is of no consequence that the cellular nucleic acid template is immobilized to the filter. All amplicon will be formed in solution. Amplicon can then be readily removed from the reaction by aspirating the liquid phase away from the FTA™ solid filter punch.
Genetic material prepared using FTA™-coated materials and FTA™ techniques yield highly purified material bound to the cellulosic base filter for the duration of various subsequent applications and amplification reactions. FTA™-coated base filter materials include, but are not limited to Whatman cellulosic BFC-180, 31-ET, glass microfiber, and any other similar filter materials known to those of skill in the art.
Genetic material can be purified from FTA™-coated material and then eluted from the filter using a combination of water, dilute organic acids such as acetic acid, and elevated temperatures. The released genetic material is a soluble fragment of varying length that is suitable for any manner of amplification and detection methodologies. The elution of the genetic material is important in applications that would not be possible if the genetic material remained bound to the FTA™-coated material. As previously mentioned, FTA™ coating can be done on other filter membrane materials additionally including, but not limited to GF/F, GF/B, QMB, Anopore, alumina, GF/M, magnetic impregnated, meltblown polymerics, and surface modified polymerics. These filter membrane materials can yield superior binding capacity, ease of elution, and extended storage of genetic material.
Biological fluid sample collection generally occurs through numerous techniques. Generally known methods include utilizing a broom-type device, swab, or spatula to obtain the sample. Then, the sample is placed onto a dry solid medium for subsequent analysis. Alternatively, the device used to obtain the sample can already have the dry solid media on it. Once the sample is on the dry solid medium, the dry solid medium can be placed on a slide, placed into a vial, a tube, or other similar apparatus for containing the dry solid medium. One apparatus is disclosed in U.S. Pat. No. 5,143,627. The '627 Patent describes an instrument for collecting a quantitatively measured number of biological cellular particles from suspension in a liquid sample and for transferring the counted collected particles, with an essentially monolayer and uniform distribution, to a viewing screen, typically a microscope slide. The instrument has disposable elements and containers that contact the sample material and accordingly require replacement between the processing of successive samples, to avoid inter-sample contamination.